| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mapdindp.h | ⊢ 𝐻  =  ( LHyp ‘ 𝐾 ) | 
						
							| 2 |  | mapdindp.m | ⊢ 𝑀  =  ( ( mapd ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 3 |  | mapdindp.u | ⊢ 𝑈  =  ( ( DVecH ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 4 |  | mapdindp.v | ⊢ 𝑉  =  ( Base ‘ 𝑈 ) | 
						
							| 5 |  | mapdindp.n | ⊢ 𝑁  =  ( LSpan ‘ 𝑈 ) | 
						
							| 6 |  | mapdindp.c | ⊢ 𝐶  =  ( ( LCDual ‘ 𝐾 ) ‘ 𝑊 ) | 
						
							| 7 |  | mapdindp.d | ⊢ 𝐷  =  ( Base ‘ 𝐶 ) | 
						
							| 8 |  | mapdindp.j | ⊢ 𝐽  =  ( LSpan ‘ 𝐶 ) | 
						
							| 9 |  | mapdindp.k | ⊢ ( 𝜑  →  ( 𝐾  ∈  HL  ∧  𝑊  ∈  𝐻 ) ) | 
						
							| 10 |  | mapdindp.f | ⊢ ( 𝜑  →  𝐹  ∈  𝐷 ) | 
						
							| 11 |  | mapdindp.mx | ⊢ ( 𝜑  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝐽 ‘ { 𝐹 } ) ) | 
						
							| 12 |  | mapdn0.o | ⊢  0   =  ( 0g ‘ 𝑈 ) | 
						
							| 13 |  | mapdn0.z | ⊢ 𝑍  =  ( 0g ‘ 𝐶 ) | 
						
							| 14 |  | mapdn0.x | ⊢ ( 𝜑  →  𝑋  ∈  ( 𝑉  ∖  {  0  } ) ) | 
						
							| 15 |  | eldifsni | ⊢ ( 𝑋  ∈  ( 𝑉  ∖  {  0  } )  →  𝑋  ≠   0  ) | 
						
							| 16 | 14 15 | syl | ⊢ ( 𝜑  →  𝑋  ≠   0  ) | 
						
							| 17 |  | sneq | ⊢ ( 𝐹  =  𝑍  →  { 𝐹 }  =  { 𝑍 } ) | 
						
							| 18 | 17 | fveq2d | ⊢ ( 𝐹  =  𝑍  →  ( 𝐽 ‘ { 𝐹 } )  =  ( 𝐽 ‘ { 𝑍 } ) ) | 
						
							| 19 | 11 18 | sylan9eq | ⊢ ( ( 𝜑  ∧  𝐹  =  𝑍 )  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝐽 ‘ { 𝑍 } ) ) | 
						
							| 20 | 1 2 3 12 6 13 9 | mapd0 | ⊢ ( 𝜑  →  ( 𝑀 ‘ {  0  } )  =  { 𝑍 } ) | 
						
							| 21 | 1 6 9 | lcdlmod | ⊢ ( 𝜑  →  𝐶  ∈  LMod ) | 
						
							| 22 | 13 8 | lspsn0 | ⊢ ( 𝐶  ∈  LMod  →  ( 𝐽 ‘ { 𝑍 } )  =  { 𝑍 } ) | 
						
							| 23 | 21 22 | syl | ⊢ ( 𝜑  →  ( 𝐽 ‘ { 𝑍 } )  =  { 𝑍 } ) | 
						
							| 24 | 20 23 | eqtr4d | ⊢ ( 𝜑  →  ( 𝑀 ‘ {  0  } )  =  ( 𝐽 ‘ { 𝑍 } ) ) | 
						
							| 25 | 24 | adantr | ⊢ ( ( 𝜑  ∧  𝐹  =  𝑍 )  →  ( 𝑀 ‘ {  0  } )  =  ( 𝐽 ‘ { 𝑍 } ) ) | 
						
							| 26 | 19 25 | eqtr4d | ⊢ ( ( 𝜑  ∧  𝐹  =  𝑍 )  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝑀 ‘ {  0  } ) ) | 
						
							| 27 | 26 | ex | ⊢ ( 𝜑  →  ( 𝐹  =  𝑍  →  ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝑀 ‘ {  0  } ) ) ) | 
						
							| 28 |  | eqid | ⊢ ( LSubSp ‘ 𝑈 )  =  ( LSubSp ‘ 𝑈 ) | 
						
							| 29 | 1 3 9 | dvhlmod | ⊢ ( 𝜑  →  𝑈  ∈  LMod ) | 
						
							| 30 | 14 | eldifad | ⊢ ( 𝜑  →  𝑋  ∈  𝑉 ) | 
						
							| 31 | 4 28 5 | lspsncl | ⊢ ( ( 𝑈  ∈  LMod  ∧  𝑋  ∈  𝑉 )  →  ( 𝑁 ‘ { 𝑋 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 32 | 29 30 31 | syl2anc | ⊢ ( 𝜑  →  ( 𝑁 ‘ { 𝑋 } )  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 33 | 12 28 | lsssn0 | ⊢ ( 𝑈  ∈  LMod  →  {  0  }  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 34 | 29 33 | syl | ⊢ ( 𝜑  →  {  0  }  ∈  ( LSubSp ‘ 𝑈 ) ) | 
						
							| 35 | 1 3 28 2 9 32 34 | mapd11 | ⊢ ( 𝜑  →  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝑀 ‘ {  0  } )  ↔  ( 𝑁 ‘ { 𝑋 } )  =  {  0  } ) ) | 
						
							| 36 | 4 12 5 | lspsneq0 | ⊢ ( ( 𝑈  ∈  LMod  ∧  𝑋  ∈  𝑉 )  →  ( ( 𝑁 ‘ { 𝑋 } )  =  {  0  }  ↔  𝑋  =   0  ) ) | 
						
							| 37 | 29 30 36 | syl2anc | ⊢ ( 𝜑  →  ( ( 𝑁 ‘ { 𝑋 } )  =  {  0  }  ↔  𝑋  =   0  ) ) | 
						
							| 38 | 35 37 | bitrd | ⊢ ( 𝜑  →  ( ( 𝑀 ‘ ( 𝑁 ‘ { 𝑋 } ) )  =  ( 𝑀 ‘ {  0  } )  ↔  𝑋  =   0  ) ) | 
						
							| 39 | 27 38 | sylibd | ⊢ ( 𝜑  →  ( 𝐹  =  𝑍  →  𝑋  =   0  ) ) | 
						
							| 40 | 39 | necon3d | ⊢ ( 𝜑  →  ( 𝑋  ≠   0   →  𝐹  ≠  𝑍 ) ) | 
						
							| 41 | 16 40 | mpd | ⊢ ( 𝜑  →  𝐹  ≠  𝑍 ) | 
						
							| 42 |  | eldifsn | ⊢ ( 𝐹  ∈  ( 𝐷  ∖  { 𝑍 } )  ↔  ( 𝐹  ∈  𝐷  ∧  𝐹  ≠  𝑍 ) ) | 
						
							| 43 | 10 41 42 | sylanbrc | ⊢ ( 𝜑  →  𝐹  ∈  ( 𝐷  ∖  { 𝑍 } ) ) |